MathDB
Problems
Contests
National and Regional Contests
PEN Problems
PEN J Problems
20
20
Part of
PEN J Problems
Problems
(1)
J 20
Source:
5/25/2007
Show that
σ
(
n
)
−
d
(
m
)
\sigma (n) -d(m)
σ
(
n
)
−
d
(
m
)
is even for all positive integers
m
m
m
and
n
n
n
where
m
m
m
is the largest odd divisor of
n
n
n
.
modular arithmetic
Divisor Functions